Hydrofluoric acid hazard potential

There is an article on HF hazard potential which I could not believe about its extent. What I know is that, if HF comes in contact with skin, it can cause burns, nasal rupture if inhaled, punctures and penetrates through the bone. But, the article mentions about its distance of impact of 2 miles from the source when travels as a cloud.
HF is used a catalyst in refineries to make high octane gasoline, as mentioned in the article. The IDLH is 30 ppm and it was found at 2 miles distance when 1000 gal was released from tanker containing 5000 gal at a pressure and temperature as used in refineries. The HF travelled as vapour and mist and needed 40 parts of water for every part of HF to dilute it, though the officials doing the experiment thought that it will remain as a liquid and can be contained. The article also mentioned about use of an additive to make HF less dangerous by way reducing its ability to form vapour cloud.
Few years ago, I read an article in the internet, in which a college girl died because of HF. When she was doing experiment, few HF drops splashed on her lab coat. She washed it with water for sometime and continued her lab work. She was found dead by her neighbours, the next day. The reason mentioned is that the vapour from lab coat was inhaled by the girl and this lead to oedema.
In a book on Bhopal accident, I read that few years before, in the same plant a similar death occurred from phosgene splash on the body. Here, the lesson is that we should not be complacent and assume that by washing for a minutes, the chemical can be cleaned. Once some chemical splashes, we should takeout the clothing. This should be followed with water wash.
Normally, as a safety precaution, one should wash for at least 15 minutes once any chemical splashes/falls on the body. Even then, studies show that only about 95% of the chemical on the skin can be washed off. During my safety lectures, I tell my audience that during the beginning of every shift, atleast once, they should check for availability of water in emergency shower/eye wash fountain and allow the water to run for few minutes so that any dirt/rust collected can run off. Else, the damage from this dirty water may be more than that from the chemical splash.

Lab Safety

Safety is freedom the danger, risk, hazard, so is the meaning found in dictionaries. All of us are concerned about our wellbeing and of others, (mostly) known and (sometimes) unknown.

While doing an activity, consciously and / or unconsciously we keep assessing the dangers in that activity and we take appropriate measures for overcoming those dangers. However, to assess / know the hazards / dangers in a work, we should have knowledge about the nature of work, the materials to be handled both manually and mechanically, the work procedure, the skills required, the persons involved, etc. Apart from these, we also should know about the area at which the work is to be done, the surroundings, the layout, the type of help that will be available in case of emergency, the exit routes, the rules and regulations of the land, etc. So, it requires lot of information to carryout a work safely so that nobody will be exposed to the dangers before, during and after the work. We give lot of importance and attention on activities in plant operations, fabrication shops, workshops, transportation, etc.

However, little attention is paid to safety during various activities in laboratory. Laboratory is a place, where we do research on small scale to establish a process, analyse various materials to know the composition, etc. Laboratory plays an important role in the establishment and various chemicals are handled for which we may not know about the dangers in handling them. The dangers can be in the form of toxicity, fire or explosion. Similarly there are dangers due to electricity, which will be used for heating, mixing, ventilation, illumination, etc. Then, big laboratories will have associated workshops to meet their various requirements, because standard equipment may not be available in the market and therefore they have to be made to the requirement of the researcher or analyst. The dangers in workshop are due to material handling, electrical and from the machines like lathes, grinders, welding sets, cutting machines and cranes and hoists. When, we start thinking about safety in lab, slowly and progressively we start identifying hazards that are present in scaled up plants and we realize that we can’t ignore safety of the people working in laboratories.

This leads us to think big and draw up a safety plan for laboratory. So what is required?

1. A well planned layout for lab, with marked locations of rooms, equipment, office rooms, storage area, air handling units for supply and exhaust ventilation, transformers, power distribution boards (PDBs), emergency exits, fire extinguishers, first aid rooms, workshop, change rooms, etc.

2. Material safety data sheets (MSDS) of the chemicals to be handled, which are available in internet in web sites like www.ilo.org, etc or if not available consult with the supplier of the chemicals. MSDS gives information about physical and chemical properties, non-compatible reactions, transportation of chemicals, measures to be taken for safety during handling and in case of emergency, spillages, etc.
3. Types and quantities of various wastes generated, storage and handling and their disposal procedure.
4. Storage of chemicals at lab stores and in the lab.
5. Power distribution and their connections to the equipment, rooms, earthing connections of equipment, earth stations / pits, earth pit and grid resistance levels to be maintained, etc.
6. Location and routing of service systems like water, air, etc.
7. Off-gas exhaust system that includes piping / ducting, filters, scrubbers, exhaust fans, discharge location (so that exhaust does not become supply for other building’s ventilation system).
8. Drains, their routing, hazards in mixing of various drains to a common drain.
9. Availability of emergency power, water, ventilation for crucial equipment / rooms.
10.Gas cylinder bank storage, movement trolleys, piping / hoses including connection arrangement, pressure regulators, pressure relief valves, monitors / detectors, exhaust system for storage.
11.Mechanical material handling systems like hoists, cranes, pallet trucks, trolleys, safe working loads (SWL), etc.
12.Location of emergency showers and eye wash fountains, availability of water, their quality, maintenance.
13.Personal protective equipment (PPE) like nose masks, respirators, goggles, face shields, aprons, suits, hand gloves, shoes, helmets.
14.In Service Inspection (ISI) requirement for various equipment like furnaces, hoods, supply and exhaust system, PDBs, process and service piping, etc.
15.Maintenance and testing procedures for equipment, electrical systems, fire extinguishers, etc.
16.Minimum inventory of chemicals, essential spares for equipment, tools, etc.

The list goes on as one thinks of and this requires constant and continuous assessment of activities for hazards and based on the activities and hazards in it, appropriate corrective measures have to be taken to minimize the hazards to acceptable levels. Some of the corrective measures in the order of priority from first to last are,

Elimination – Stop use or preparation of chemical so that the hazard can be totally avoided.
Substitution – Find an alternate chemical or method by which the level of hazard can be reduced to acceptable levels.
Administrative – Devise and implement administrative controls so that safe handling can be ensured.
Training – Provide training and retraining to people so that they understand what they are doing, hazards in it and protective measures to be followed and what to do in case of any emergency.
PPE – Use of personal protective equipment (PPE) is the last line of defense and PPE as appropriate to the need is to be used correctly so that persons will be protected when all other lines of defense mechanisms fail.

Finally, an emergency plan should be available for meeting all possible situations, mock drills have to be conducted to ensure that every body understands what is their role and responsibility in an emergency and drawbacks found in mock drills are to be corrected so that a fool-proof emergency plan will be in place.

Finally, I want to remind all concerned about Murphy’s Law, which states, “If something can go wrong, it will and what is more, it will probably happen when we are least expecting it. It may also occur at the worst possible moment, when we are least able to react quickly and effectively because, we have our hands already full or our attention is elsewhere”.

And, “Those who cannot remember the past are condemned to repeat it - George Santayana”

For those who are interested in safety, a number of e-books are available at www.ebookee.com and www.esnips.com. Apart from these, accident investigation reports are available at www.csb.gov and www.hse.gov.uk.

Wish you all a safe lab experience.